Question

Find the area of circle length of whose circumference is equal to the sum of the lengths of the circumference with radis 15cm and 13 cm

Answer 1

$c = c1 + c2 = \pi(2 \times 15 + 2 \times 13) \\ 2\pi \: r = \pi \: \times 56 \\ r = 28cm \\ area = \pi {r}^{2} \\ = \frac{22}{7} \times 28 \times 28 \\ = 22 \times 4 \times 28 \\ = 88 \times 28 \\ = 2464 {cm}^{2}$